1. Field of the Invention
This invention relates to wireless private branch exchange (PBX) systems and more particularly to an arrangement for automatically configuring a plurality of terminals for operation within such a PBX system.
2. Description of the Prior Art
In a PBX (or Key) system, a number of lines are provided between a group of local users and a switch in the PBX system. Through these lines, the PBX system provides a certain number of accesses to a remote communications exchange and also provides access for the local users to each other. A call made to or from the remote communications exchange must first access the switch, which then routes the call to its destination. A call made from one local user to another must also access the switch which similarly routes the call to its destination. Even though the PBX switch reduces the number of lines between the group of local users and the remote communications exchange, a substantial amount of wiring is still required between the switch and the local users.
Both a customer and a manufacturer of PBX systems benefit when the amount of wiring required for installation of the PBX system is reduced. If installable by the customer, such a system, has the potential of saving both time and expense for the customer, while providing a marketing advantage for the manufacturer. Much of the equipment for small PBX systems is compact and self-contained enough for customers to install, but the wiring between the local units and the PBX switch generally requires outside help for both new installations and moves or rearrangements. If the wiring is eliminated or substantially simplified, most customers could install or rearrange the equipment as appropriate without assistance.
To this end, wireless multiple access communication systems have been successfully implemented in PBX type applications. An example of such a system is a spread spectrum wireless PBX system described in U.S. Pat. No. 4,672,658 which issued to M. Kavehrad, et al. on Jun. 9, 1987 In this system, each one of local user transceivers is matched to a separate one of multiple PBX transceivers. Although this system provide wireless communications, it does not readily permit customer installation or rearrangement of the system equipment. This system is also burdened by spread-spectrum technology which uses a fairly complex design.
Wireless multiple access communication systems have also been successfully implemented in certain other applications. For example, a mobile radio system simultaneously routes a plurality of private communications through a central base station which performs the switching necessary to interconnect the appropriate users, utilizing frequency shift keying (FSK) modulation and frequency division multiple access (FDMA). In this regard see, for example, U.S. Pat. No. 4,112,257 which issued to E. G. Frost on Sep. 5, 1978. Another radio system is the satellite-based communications system described in U.S. Pat. No. 4,291,409 which issued to A. Weinberg et al. on Sep. 22, 1981, wherein a central switching arrangement, phase shift keying (PSK) modulation and spread spectrum multiple access (SSMA) are used. Like the above described PBX system, these systems do not not readily permit customer installation or rearrangement of the system equipment. Site engineering or trial-and-error placement of equipment within the system is therefore generally required. Moreover, these systems are either limited in range due to transmitter power constraints that exist under present regulations, or are also burdened by complex spread-spectrum designs.